Double stacked trucks for skateboards

ABSTRACT

A skateboard with double trucks, which are in a stacked array, for increased turning ability, shock absorption, flexibility, control and traction.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to skateboards with improvedmaneuverability, and in particular to a skateboard with double trucks,which are in a stacked array, for increased turning ability, shockabsorption, flexibility, control and traction.

2. Description of the Prior Art

The sport of skateboarding has exploded in popularity in recent years.The competitive sport of skateboarding includes many different styles ofcompetition. For example, trick riding, slalom, downhill, etc., are justsome of the variations that have recently developed. The more seriousskateboarding pursuits subject skateboards to exacting performancecharacteristics. The most functional performance characteristics arecontrolled by the truck or chassis of the board. The truck controls thestability, maneuverability, and handling of the board. Each of the modesof skateboarding requires a different truck performance for optimumskateboard performance.

The prior art construction of skateboard truck chassis are exemplified,for example, by U.S. Pat. No. 3,862,763, issued Jan. 28, 1975, to GordonK. Ware. The prior art skateboard truck assembly typically employ anarrangement wherein the pivot axis is approximately 45 degrees with theweight of the board supported predominantly on tension pads, which areoriented substantially vertically or at most a few degrees up toapproximately 15 degrees off the vertical, such as illustrated in theWare patent. The arrangement is such that the tension in the pads can beadjusted by adjustment of the tension bolt and this can provide minoradjustments in the pivot axis of the truck assembly. However, there isno independent adjustment of the pivot axis independently of theadjustment of the tension in the tension pad. Moreover, with thisarrangement, the tilting of the board with respect to the chassis, whichresults in the major control and steering of the board is resistedpredominantly by the pads. The tilt is also at substantially rightangles to the axis of the tension bolt, resulting in high stress on thetension bolt.

Conventional trucks follow a basic design in which an axle pivots aboutan arm attached at one end to the center portion of the axle. The otherend of this pivot arm is loosely fitted, at an angle of approximately 45degrees, into a plastic cup mounted in a baseplate, thus forming aball-like joint. A pair of doughnut-shaped grommets, usually made ofrubber or urethane plastic of various hardnesses, is mounted on asubstantially vertical kingpin fixed in the baseplate on the side of theaxle opposite the plastic cup. These grommets grasp a ring extendingfrom the axle body so that the axle is suspended between the ball-likejoint and the grommets.

By adjusting the kingpin, the tension on the grommets may be increasedor decreased, thereby varying the balance between turning stability andturning ease. The kingpin employed in conventional trucks is oriented ata substantially right angle to the tilting movement of the deck,resulting in high stress on the kingpin. Because the kingpin and thegrommets do not adequately stabilize the pivot arm axis, and because ofthe loose fit between the pivot arm and the plastic cup, the angle ofthe pivot axis tends to deteriorate as the axle tilts, so that verytight turns may be difficult or impossible to achieve.

A further drawback of this standard design is that the suspension systemformed by the plastic grommets fails to provide fine steering control.Riders control the angle of the deck's tilt, and thus the size of theturns they make, by varying the distance by which they shift theirweight laterally across the width of the deck. Regardless of theirhardness or of how they are adjusted, the standard urethane grommets donot offer a regular, orderly pattern of resistance to such weightshifts. The result is that the riders cannot easily predict or measurehow far they must shift their weight to achieve steering radii ofvarious sizes.

Typically a truck is mounted near each end of the skateboard, andincludes a pair of wheels at each end of its axles. In such assemblies,the truck normally positions the angle of turning of the axles andwheels at a 45 degree angle to the board. Accordingly, tilting movementof the board causes a turning moment to the axle and thus the wheels.The trucks provide steering response when a skateboarder shifts his orher weight laterally across the board, whereby the axle twists, causingthe board to turn. The trucks also serve, by means of a suspensionsystem, commonly urethane bushings, to resiliently resist the skater'slateral tilt of the deck, thus stabilizing the board, and returning itto its normal position when the turn is completed.

The general object of the skateboard suspension system is to provideride smoothness, general board stability, and turning ability, through arelatively inexpensive, standardized truck assembly. The standardizedtruck assemblies are normally standardized at the angle of axle pivot of45 degrees. This provides medium turning ability with compromisedinstability at relatively high speeds.

Wider turning ability can be achieved by loosening the kingpin, whichresults in less control and less responsiveness for performing variousdesired maneuvers. The prior art has not adequately addressed theproblem of providing wider turns and sharper turns while maintainingfirm control with a tight responsive truck.

Prior art U.S. Patent Application #20020125670, published Sep. 12, 2002by Stratton, puts forth a skateboard truck that provides a combinationof adjustable lateral stability and enhanced turning abilities. Theskateboard truck comprises a base attachable to the underside of askateboard and an arm carried by the base and rotatable relative to thebase about a first axis. The skateboard truck has an axle with a pair ofwheels mounted at opposite ends thereof is carried by the arm and theaxle is rotatable relative to the arm about a second axis. Aspring-loaded linkage is operatively connected between the base and thearm for limiting the rotational motion of the arm and biasing the armtowards a center position aligned with the skateboard's direction ofmovement. The first and second axes provide pivoting of the skateboardin two dimensions.

Prior art U.S. Pat. No. 5,853,182, issued Dec. 29, 1998 to Finkle,provides a truck assembly with skateboards where the axle assembly issupported on an elastomeric bumper, which in turn is supported on anangled shaft. As the skateboard is tilted, the bumper is twisted,causing the axle of the skate assembly to tilt and turn. The bumper isheld at one end to the base and at the other end to the axle assembly.

Prior art U.S. Pat. No. 6,206,390, issued Mar. 27, 2001 to Borg, shows askateboard apparatus for higher turning capabilities. The skateboardapparatus includes a board for supporting a user. The board has a topsurface, a bottom surface, a front end and a back end. A first wheelassembly is coupled to the bottom surface of the board. The first wheelassembly is positioned generally nearer the back end than the front end.A second wheel assembly is coupled to the bottom surface of the boardand is positioned generally nearer the front end than the back end ofthe board. The second wheel assembly generally comprises an axle and apair of wheels. The axle is adapted to rotate with respect to alongitudinal axis of the board. A steering assembly is used for alteringthe rotational direction of the wheels of the second wheel assembly. Thesteering assembly has a first end coupled to the second wheel assembly.The steering assembly extends away from the second wheel assembly suchthat a user may grasp a free end of the steering assembly.

Prior art U.S. Pat. No. 4,060,253, issued Nov. 29, 1977 to Oldendorf,claims a method and apparatus for a skateboard suspension system. Anglepads are removably sandwiched between the truck assemblies and boards ofskateboards. The pads have upper and lower surfaces with differentinterface angles with the respective truck assemblies and boards, thatincrease or decrease the pivot angle of the truck assemblies relative tothe boards and thus selectively change the amount of board tilt requiredto provide a desired turning of the axles and wheels through the truckassemblies. Thus the angle pads allow selective changing of themagnitude of turning of either the front or rear truck assemblies andwheels to achieve exceptional turning ability or high speed stability.

Prior art U.S. Pat. No. 5,263,725, issued Nov. 23, 1993 to Gesmer,describes an improved skateboard truck that incorporates exceptionallyrapid and consistently accurate axle rebound to the straight-aheadposition, consistent and predictable steering response, an improvedbalance between stability and maneuverability, fine steering control,and a wide range of steering radii. A yoke containing the truck axleincludes a central body portion with a central aperture therein for apivot pin. Sockets for containing the ends of coil springs are formed inthe yoke on either side of the yoke's central aperture. A baseplateincludes a second aperture for receiving the end of the pivot pin, andthe pivot pin itself extends through the yoke into the baseplate. Secondsockets for receiving the other ends of the coil springs are also formedin the baseplate on either side of the second aperture, and the coilsprings themselves extend from the sockets in the yoke to the sockets inthe baseplate. The sockets are conically shaped. As the yoke turns,pivoting the wheels on the outer ends of the yoke in a very fixed arcabout the pivot pin, the coil springs remain substantially columnar andunbuckling as they pivot at each of their ends in the sockets' bases.

Prior art U.S. Pat. No. 5,997,018, issued Dec. 7, 1999 to Lee, disclosesan all-terrain sport board especially adapted for riding on roughout-door terrain employing large pneumatic wheels, a large frame and aspring steering mechanism that enables a rider to tip the board and turnthe wheels to a much greater degree than would be possible with aconventional boards. The steering mechanism provides polymeric shockabsorbers of varying configurations to enhance the ability of the riderto make athletic maneuvers and jumps with the board without undueturbulence in the ride.

Prior art U.S. Pat. No. 4,645,223, issued Feb. 24, 1987 to Grossman,indicates a skateboard assembly that has greatly improved riding andhandling characteristics. The assembly includes a skateboard, aplurality of spaced wheel axles and rotatably secured sets of wheels andelongated resilient suspension frames connected at their opposite endsthrough housings to the wheel axles and to the underside of theskateboard. The assembly has at least four different shock-absorbingsystems. Thus, the frames themselves absorb shock, as do cylinders ofresilient rubber or the like set in cups connected to the frames abovethe wheel axles and bearing against the underside of the board. Thewheel axle housings also include resilient dampeners, which adjustablyrestrict steering rotation of the wheel axles and additionally dampenshocks. The frame housing connected to the underside of the skateboardrotatably receives the bases of the frames and adjustably controls thatrotation, while providing a shock absorbing function, through the use ofresilient bushing around the frame bases. The bushings are adjustablycompressible thereagainst by adjustably tightening the frame housingagainst the underside of the skateboard. The assembly is simple,inexpensive, durable and efficient, imparting greatly improved ridingand handling characteristics to the skateboard.

Prior art U.S. Pat. No. 5,522,620, issued Jun. 4, 1996 to Pracas, putsforth a skateboard truck for a skateboard that has a pivotal member,which is connected to the deck of the skateboard. The pivotal membercarries the wheel assembly of the truck. A locking mechanism is alsoprovided. In a first (unlocked) mode of operation, the pivotal member isable to pivot so that the truck is movable in a to and fro manner. Thisfirst mode of operation permits a rider to perform advanced maneuversusing a skateboard. In a second (locked) mode of operation, the truck islocked against such to and fro movement by the locking mechanism.

Prior art U.S. Pat. No. 6,547,262, issued Apr. 15, 2003 to Yamada,concerns an improved truck assembly for skateboards and street luges,which provides speed and fast reaction maneuverability. The preferredskateboard truck comprises a yoke mounted by a king bolt to a mountingbase. The mounting base comprises a socket hub and a bracket. The yokecomprises a hanger and a pivot arm. The pivot arm rotates freely in abearing unit supporting the pivot arm in the socket hub. The king boltclamps the hanger with a first grommet and a second grommet. The firstgrommet is flexible, preferably made of urethane rubber, and comprisesan edge circumference and a center circumference. The centercircumference is narrower than the edge circumference. Preferably, thefirst and second grommets are fluorescent.

Prior art U.S. Pat. No. 6,182,987, issued Feb. 6, 2001 to Bryant,illustrates an improved skate or skateboard, which incorporatesprecision steering and rocking components for consistency and accuracyduring maneuvers and a method for removing or replacing worn or brokenaxles. A yoke containing the truck axle includes a central body portioninto which a precision ball socket has been machined. It is jointed by aspherical component for the yoke to pivot around. It is also fitted witha precision ball pivot pin opposite the socket, which will act as theassociate pivotal and rocking mechanism for the truck assembly. The baseis comprised of a central body into which a stud is secured for mountingthe yoke and a pocket has been machined for containing a precision ballsocket to accept the associate ball pivot pin. A slotted configurationsituated at each end of the yoke can be compressed with screws to allowthe axle to be removed or replaced.

Prior art U.S. Pat. No. 6,224,076, issued May 1, 2001 to Kent, is for apneumatic compression strut skateboard truck, which is intended for usein street and off-road skateboarding. The truck utilizes a pneumaticcompression strut suspension system, which is of the same type and kindused in automobiles and other mechanical devises employing shockabsorbing technology. The compression struts resist pressure in thedirection of their length, thereby decreasing or eliminating shockforces associated with street and off-road skateboarding. By reducing oreliminating these extreme forces, the skateboarder has moremaneuverability and control. Further, it reduces or eliminates the shockforces that would normally be transferred to the skateboarder. This willcontribute to the decrease in stress and fatigue of the skateboarder'sextremities and therefore increase endurance.

Prior art U.S. Pat. No. 4,194,752, issued Mar. 25, 1980 to Tilch,provides a skateboard that comprises an elongated board and a pair oftrucks mounted adjacent opposite ends of the board, each truck has apair of rotatable wheels. Each truck consists of a tensile elasticsuspension member and a pivot support consisting of a universallymovable ball and socket joint. The novel features of construction andarrangement of the skateboard assembly provide improved steering actionof the axles relative to the board, wherein the energy for steering andaccelerating the skateboard is substantially reduced.

Prior art U.S. Pat. No. 4,109,925, issued Aug. 29, 1978 to Williams etal., describes a skateboard truck including an axle assembly which isquickly detachable from the truck mounting pad by means of a tensionbolt fitting within a slotted bracket in the mounting pad for quickdetachment therefrom. The skateboard truck assembly is provided with atension screw assembly that is mounted at a less than 45 degree anglewith respect to the skateboard and includes adjusting means foradjusting the pivot axis of the assembly with respect to the skateboard,totally independent of the adjustment of the tension in the assembly. Asafety bracket includes a base portion with an arm having a cylindricalbore for receiving the cylindrical outer end of the tension bolt forreducing the stress on the board or tension bolt during the steering ofthe skateboard.

It is therefore advantageous to have a new and improved skateboardsuspension system, in which high speed stability can be achieved alongwith exceptional turning ability providing wider turns and sharper turnswhile maintaining firm control with a tight responsive truck.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a new and improveddouble stacked truck skateboard suspension system, in which high speedstability can be achieved along with exceptional turning abilityproviding wider turns and sharper turns while maintaining firm controlwith a tight responsive truck.

Another object of the present invention is to provide a double stackedtruck skateboard suspension system with two kingpins and two sets ofgrommets stacked on top of each other to effectively double the turningcapability while maintaining the desired tension in each of the kingpinsfor optimum control and performance characteristics.

One more object of the present invention is to provide a double stackedtruck skateboard suspension system that may have first and second truckswith similarly angled kingpins, wherein both trucks are regular type orboth trucks are Randal type trucks.

An additional object of the present invention is to provide a doublestacked truck skateboard suspension system that may have first andsecond trucks with differently angled kingpins, wherein the first truckis a regular type truck and the second truck is a Randal type truck orthe first truck is a Randal type truck and the second truck is a regulartype truck.

A further object of the present invention is to provide a new andimproved double stacked truck skateboard suspension system that has anovel pivot pin built into the top of the second truck kingpin, whichengages a receiving recess in the face of the base plate.

In brief, a pair of pivoting trucks are stacked on top of each other,preferably welded together, with the topmost truck having the axleportion removed to reduce the overall height of the double stackedtruck. The trucks may be two regular (independent brand type) truckswelded together and mounted on a plate on the bottom of the board. Thereis also an alternate type truck called a “Randal” truck used by high endskaters and long boarders and has different handling and turningcapabilities. The Randal truck can be stacked onto a regular truck baseor two Randals stacked together or a regular stacked on a Randal asdesired for different performance characteristics.

The difference between the two types of trucks is in angle of thekingpin bolt. Randal trucks have the kingpin starting on the outsideedge of the board and angled sharply (towards the two ends) and theregular truck has the kingpin located to the inside of the axles withthe kingpin in a vertical orientation. Randal trucks make the axle twistin a horizontal fashion and the regular trucks cause the deck to tiltmore. Randals trucks were developed to help control speed wobbles. Thekingpin of the second truck may further comprise a novel pivot end,which is insertable in the face of the base plate.

An advantage of the present invention is that it provides increasedturning ability and greater maneuverability.

An additional advantage of the present invention is that it providesbetter shock absorption.

One more advantage of the present invention is that it providesincreased flexibility.

Yet another advantage of the present invention is that it providesincreased control and traction.

Another advantage of the present invention is that it can use standardor Randal trucks.

Still another advantage of the present invention is that it isinexpensive to manufacture.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other details of my invention will be described in connectionwith the accompanying drawings, which are furnished only by way ofillustration and not in limitation of the invention, and in whichdrawings:

FIG. 1 is a perspective view of a first regular type truck mounted on abase plate under a skateboard, the first truck having no axle and asecond regular type truck mounted on the first truck;

FIG. 2 is a perspective view of a first regular type truck mounted on abase plate under a skateboard, the first truck having no axle and nopivot pin and a second regular type truck mounted on the first truckwith the kingpin of the second truck having a top pivot pin inserted inthe base plate;

FIG. 3 is a perspective view of a first regular type truck mounted on abase plate under a skateboard, the first truck having no axle and asecond Randal type truck mounted on the first truck.

BEST MODE FOR CARRYING OUT THE INVENTION

In FIGS. 1-3, a double stacked truck system 20 or 20A for skateboardsthat comprises a first truck 22A, which is attached to a base plate 25mounted on an underside of a skateboard 30 at each end of theskateboard. The first truck 22A comprises an adjustable kingpin 23A andgrommet configuration 21A and is reduced in height by having no axle.The double stacked truck system 20 or 20A also comprises a second truck22B that is attached to the first truck 22A, preferably by a weldedjoint 29 or other means to join the two trucks 22A and 22B together. Thesecond truck 22B comprises an adjustable kingpin 23B and grommetconfiguration 21B and an axle 41 and pair of wheels 40 so that the firstand second truck 22A and 22B combine to create a stacked truck 20 or 20Ahaving two cooperative kingpin 23A and 23B and grommet configurations21A and 21B for a single axle 41 and pair of wheels 40, thereby doublingthe turning and maneuvering capability of the skateboard. The kingpin23B of the second truck 22B may further comprise a pivot end 27, whichis insertable in the face 26 of the base plate 25, as shown in FIG. 2,rather than each truck having a separate pivot pin.

The first and second trucks 22A and 22B may have similarly angledkingpins 23A and 23B, wherein both trucks 22A and 22B are regular type,as shown in FIGS. 1 and 2, or both trucks 22A and 22B are Randal typetrucks (configuration not shown).

The first and second trucks 22A and 22B may alternately have differentlyangled kingpins 23A and 23B, wherein the first truck 22A is a regulartype truck and the second truck 22B is a Randal type truck, as shown inFIG. 3, or the first truck 22A is a Randal type truck and the secondtruck 22B is a regular type truck (configuration not shown).

The topmost truck 22A is mounted on a base plate 25 by bolting thekingpin through an opening in one face 28 of the base plate 25, whichwould then be mounted on the bottom of the skateboard 30, as shown inFIGS. 1 and 2, or on a base plate 25 mounted in a recess 31 in the board30 as shown in FIG. 3. The pivot pin 27 engages a recess in the otherface 26 of the base plate.

In practice, a user may increase or decrease the tension of the grommets21A and 21B on the trucks 22A and 22B by adjusting the kingpins 23A and23B, thereby varying the balance between flexible maneuvering andcontrol.

It is understood that the preceding description is given merely by wayof illustration and not in limitation of the invention and that variousmodifications may be made thereto without departing from the spirit ofthe invention as claimed.

1. A double stacked truck system for skateboards comprising: a firsttruck attached to a base plate mounted on an underside of a skateboardat each end of the skateboard, the first truck comprising an adjustablekingpin and grommet configuration, the first truck reduced in height byhaving no axle; a second truck attached to the first truck, the secondtruck comprising an adjustable kingpin and grommet configuration and anaxle and pair of wheels so that the first and second truck combine tocreate a stacked truck having two cooperative kingpin and grommetconfigurations for a single axle and pair of wheels.
 2. The system ofclaim 1 wherein the kingpin of the second truck further comprises apivot end insertable in the base plate.
 3. The system of claim 1 whereinthe first truck and the second truck are welded together.
 4. The systemof claim 1 wherein the first and second trucks have similarly angledkingpins.
 5. The system of claim 4 wherein the first and second trucksare both regular type trucks.
 6. The system of claim 4 wherein the firstand second trucks are both Randal type trucks.
 7. The system of claim 1wherein the first and second trucks have differently angled kingpins. 8.The system of claim 7 wherein the first truck is a regular type truckand the second truck is a Randal type truck.
 9. The system of claim 7wherein the first truck is a Randal type truck and the second truck is aregular type truck.